Cable tie with two metallic pawls



Aug. 20, 1968 c. F. PEARL CABLE TIE WITH TWO METALLIC PAWLS Filed June 1, 1967 INVENTOR. C'l/Rf/S FT PEARL 6 4 7'702IVEX United States Patent C) 3,397,430 CABLE TIE WITH TWO METALLIC PAWLS Curtis F. Pearl, Teaneck, N.J., assignor to Eiectrovert, Inc., Mount Vernon, N.Y. Filed June 1, 1967, Ser. No. 642,900 Claims. (CI. 24-16) ABSTRACT OF THE DISCLOSURE The disclosure is directed to a cable tie for binding plural insulated conductors or the like into a cable. The tie includes a relatively elongated substantially flat flexible tongue having an open frame integral with one end thereof, the frame and the tongue preferably being formed of a plastic composition material or synthetic resin. The frame has end and side walls defining a substantially rectangular opening to receive the opposite end of the tongue, which latter is inserted through a tongue entry face in the frame and is drawn outwardly through a tongue exit face.

A pair of metallic pawls are provided, each having a fixed end mounted in a respective frame Side wall, these pawls having free ends extending inwardly toward each other and converging toward the exit face of the frame. The free ends of the pawls are spaced a substantial distance inwardly of the exit face of the frame. The pawls flex as the cable tie tongue is drawn through the frame, then bite into the side edges of the tongue to prevent retraction of the latter through the frame.

Due to the location of the free ends of the pawls a substantial distance inwardly from the exit face of the frame, the projecting portion of the tongue may be cut off just outwardly of the free ends of the pawls, with the cut end of the cable tie being located completely within the frame.

Background of the invention In the installation of wiring harnesses in various locations, such as in wiring aircraft, automobiles, switch boards and the like, several insulated conductors have been tied together at spaced points or have been laced together. Thereby, a multi-conductor cable is formed which can be mounted at spaced points on a supporting surface or on other supporting means. While the conductors can be formed into a cable merely by tying them with a cord at spaced points therealong, or by wrapping a wire therearound and twisting the ends of the wire together, these more or less non-permanent and time-consuming tying means have been found to be generally unsatisfactory in practice. There has been, accordingly, a demand for a simple, inexpensive, preformed cable tie for readily and easily binding a group of insulated conductors, for example, into a cable.

Various cable ties have been proposed for this purpose, and among these may be particularly mentioned that shown in Schwester et al. U.S. Patent No. 3,186,047, issued June 1, 1965. The cable tie shown in the Schwester et al. patent includes an elongated tongue of plastic material, an open frame head at one end of the tongue adapted to receive the other end of the tongue, and a metal pawl mounted in the head and adapted to cooperate therewith to allow drawing of the tongue through the head while preventing retraction of the tongue in the opposite direction. The head of the Schwester et al. bundling strap or cable tie is enlarged relative to the tongue portion in both lateral directions.

In particular, in the tongue drawing direction, the head is very substantially thicker than the tongue, and the head is formed with a passage extending therethrough having dimensions in excess of the thickness and width of the tongue. The exit side of the head is formed with aligned rectangular slots extending centrally across the aperture ice therethrough to both sides of the aperture. The outer one of these slots provides clearance for insertion of the metal pawl into the inner slot and into the material of the head, with the pawl extending at substantially a 45 angle to the direction of passage of the tongue through the head aperture and extending across the axis of this receiving aperture.

When the tongue of the Schwester et al. bundling strap or cable tie is drawn through the aperture in the head, the metal pawl flexes to allow such drawing of the tongue tightly about a bundle of conductors. However, upon the tongue tending to retract through the head, a chisel edge on the pawl bites into a portion of one of the wider surfaces of the tongue and tends to resist retraction of the tongue. The metal pawl of Schwester et al. is very substantially narrower than the tongue of the cable tie, and, in effect, engages or digs into the cable tie only across a pair of relatively closely spaced ribs extending longitudinally of the cable tie. Additionally, the adjacent surfaces of the rectangular slot in which the metal pawl is mounted are spaced very substantially from the surfaces of the pawl, so that the pawl has a wide range of movement or fiexure before it will engage or rest against either one of the facing surfaces of the mounting slot. Furthermore, the chisel edge, which is engageable with the tOngue of the cable tie, is very close to the exit surface of the head, and is almost flush therewith.

This latter fact is a disadvantage of the Schwester et al. cable tie as well as most other known cable ties. In practice, after the tongue has been drawn through the head of the tie to a cable tightening position, the projecting end of the tongue is severed, as by cutting or nipping off the projecting portion. This generally leaves a small cut end portion of the tongue projecting outwardly of the head of the cable tie, and this is unsatisfactory for many applications. It is not possible, in the cable tie shown by Schwester et al., to cut the tongue substantially flush with the outer or exit surface of the head, as this would result in release of the tongue from the chisel edge of the pawl. Consequently, a small length of the tongue has to be left projecting from the head and extending beyond the outer surface thereof.

The cable tie shown by Schwester et al. has a further pronounced disadvanage. Upon reverse stress upon the tongue, the relatively great spacing between the surface of the pawl and the adjacent surface of the rectangular slot in the head, in which the pawl is mounted, allows very substantial rearward flexing and bending of the pawl, to an extent that the pawl will disengage the tongue and allow loosening of the cable tie. This is due to the very extended unsupported length of the metal pawl of Schwester et al. A further disadvantage is that all of the holding stress of the cable tie, when wrapped tightly around a bundle of cables or conductors, is concentrated in the relatively narrow or short chisel edge of the single metal pawl of Schwester et al.

U.S. patent application Ser. No. 592,352, filed by George A. Orban on Nov. 7, 1966, and now U.S. Patent No. 3,368,247, discloses a cable tie in which this disadvantage, with respect to a projecting cut edge of the tongue, is eliminated. The Orban. cable tie is a onepiece element of flexible plastic composition material including a tongue and a head, the head being in the form of a rectangular frame defining a substantially rectangular opening for the free end of the tongue to be drawn through the frame. At least a portion of one relatively wider surface of the tongue is formed with a series of serrations extending there across, and the head or frame is formed with an integral pawl having a transversely extending chisel edge which is arranged to engage these serrations when the tongue portion of the cable tie is drawn through the head. This pawl has its outer edge located a definite distance inwardly from the exit surface of the head. Consequently, when the cable tie tongue is drawn through the head thereof, the pawl can engage these serrations to prevent retraction of the tongue or leesening of the cable tie. Most importantly, due to the location of the pawl a substantial distance inwardly from the exit face of the head, the projecting portion of the tongue of the cable tie may be cut off in such a manner that the cut edge is disposed inwardly of the exit face of the tongue. Thus, there is no cut edge of a tongue portion of a cable tie projecting outwardly of the head portion of the cable tie after the cable tie has been drawn tightly around a group of insulated conductors or the like, and the projecting portion of the tongue cut off.

The cable tie shown in the above-mentioned Orban patent application has proven very satisfactory in practice, particularly with respect to the location of the cut end of the tie within the frame and not projecting therefrom. However, due to the fact that the pawl is made of plastic and is engaged with a plastic tongue, the provision of the serrations is necessary in order to insure a firm gripping action of the plastic pawl on the plastic tongue. Additionally, the Orban cable tie requires rather intricate molds for its manufacture, and the cost of these molds, as compared to the cost of a relatively simple mold, increases to some extent the cost of the cable tie molded therein.

Accordingly, it is desirable to provide a cable tie which have the advantages of the Orban cable tie, with respect to tongue gripping power and location of the cut end of the tongue within the frame, without the disadvantages, such as a relatively higher cost, of the Orban cable tie.

Summary of the invention The present invention is directed to a novel, inexpensive and simply applied cable tie or the like which has the advantages of the Orban cable tie but which utilizes metal pawls which will bite into the material of the plastic tongue and eliminate the necessity for forming the tongue with the transversely extending serrations. Additionally, the formation of the head or frame end of the cable tie is greatly simplified with respect to molding operations, thereby reducing the overall cost of the cable tie, relative to that shown in the mentioned Orban patent application, while retaining all of the outstanding advantages of the cable tie shown in the mentioned Orban patent application.

In accordance with the present invention, a cable tie is provided which includes a relatively elongated substantially flat flexible tongue preferably molded of plastic composition material, the cable tie further including a substantially rectangular open frame integral with one end of the tongue. This frame includes substantially parallel inner and outer end walls interconnected by substantially parallel side walls to define a substantially rectangular opening to receive the opposite end of the tongue after the tie has been wrapped around plural insulated conductors or the like to draw the same into a cable. The frame has a tongue entry face and a tongue exit face, and in accordance with the invention, those surfaces of the side walls facing toward the tongue exit face are spaced a substantial distance inwardly from this exit face.

A pair of metallic pawls are provided, each having a fixed end mounted in a respective frame side wall, these pawls having free ends extending inwardly toward each other and converging toward the exit face of the frame. The pawls are so mounted in the side Walls that their free ends are spaced a substantial distance inwardly of the exit face of the frame.

As the tie is wrapped around the plurality of insulated conductors or the like, and the tongue inserted through the frame, the pawls flex as the tongue is drawn through the frame and bite into the side edges of the tongue to prevent the retraction of the latter through the frame.

A feature of the invention is that the pawls are so inserted into the respective side walls of the frame that there is a limited clearance between the inner surface of each metal pawl and an adjacent portion of the associated side wall, and a relatively large clearance between the outer surface of each pawl and a surface of the respective side Wall. This facilitates flexing of the pawls as the cable tie tongue is drawn through the frame of the cable tie. Due to the recessing of the exit surfaces of the frame side Walls, the projecting portion of the tongue can be cut off well inwardly of the exit face of the frame, so that the cut edge of the tongue is protected by the spaced parallel end walls of the frame and is inwardly a substantial distance from the exit face of the frame.

An important feature of the invention, as distinguished from mentioned Schwester et al construction, is that the two metal pawls have only a very short unsupported length engageable with the side edges of the tongue. This avoids backward bending or flexing of the pawls when a retracting force is imposed upon the tongue of the cable tie. After only a minute backward movement of the cable tie, the pawls engage supporting surfaces of the notches in which they are set, and only a relatively minute length of each metal pawl projects beyond the associated supporting surfaces. Additionally, the total stress on the cable tie is divided equally between the two metal pawls, each of which has a width in excess of the thickness of the tongue of the cable tie.

An object of the present invention is to provide a cable tie of the genearl type mentioned above but in which, after severing of the extra length of the tongue projecting from the frame or head portion, the cut edge of the tongue not only does not project beyond the exit surface of the frame but is actually disposed inwardly thereof.

Another object of the invention is to provide a cable tie having the feature just mentioned but having an improved gripping action on the cable tie tongue drawn through the cable tie frame or head.

A further object of the invention is to provide a cable tie of the type mentioned above in which the tongue gripping action is provided by a pair of flexible metallic pawls each mounted in a respective side Wall of a substantially rectangular frame.

Yet another object of the invention is to provide a cable tie of the type mentioned in the preceding paragraph and in which the wider surfaces of the flat flexible tongue can be substantially smooth and does not need to be formed with transversely extending serrations.

A further object of the invention is to provide a cable tie of the type mentioned in the preceding paragraphs and which is simple and inexpensive to manufacture and effective in operation.

Brief description of the drawings For an understanding of the principles of the invention, reference is made to the following description of typical embodiments thereof as illustrated in the accompanying drawings.

In the drawings:

FIG. lis an enlarged partial plan view of one surface of the cable tie embodying the invention;

FIG. 2 is a partial longitudinal sectional view of the head of the cable tie;

FIG. 3 is an enlarged partial plan view of the opposite surface of the cable tie;

FIG. 4 is an elevational view, partly in section, of the cable tie as applied to bundle a group of insulated conductors into a cable;

FIG. 5 is a sectional view taken on the line 55 of FIG. 4; and

FIG. 6 is a partial perspective view illustrating a modification of the cable tie shown in FIGS. 1 through 5.

Description of the preferred embodiments As illustrated in FIGS. 1 through 5 of the drawings,

the cable tie of the invention, generally indicated at 10, is a substantially fiat and elongated flexible strip which is molded from a suitable plastic composition or synthetic resin. Solely by way of example, cable tie may be molded from a nylon resin.

Cable tie 10 includes a relatively elongated tongue having a rectangular frame or head integral with one end thereof. The opposite end of tongue 15 is gradually reduced in thickness and width as indicated at 16, to form a tapered end portion for a purpose to be described hereinafter. Tongue 15 includes substantially fiat relatively wide surfaces 18, 18 and side edges 17, 17, and one surface 18 may be formed with projections 12 to facilitate gripping of the tongue and drawing the tie around a bundle of conductors.

Head 20 is in the form of a substantially rectangular frame which is wider than tongue 15 and which has a tongue entry face 21 which is substantially flush with one surface 18 of tongue 15. The frame or head 20 includes substantially parallel inner and outer end walls 22 and 23, respectively, which are interconnected by substantially parallel side walls 24. Inner end wall 22 is substantially trapezoidal in cross section, with its outer sloping surface 26 merging substantially smoothly with a surface 18 of tongue 15. The substantially coplanar surfaces of end walls 22 and 23, opposite those surfaces of the end walls included in the tongue entry face 21, define tongue exit surfaces or faces 27. It will be noted that those surfaces 28 of side walls 24 facing toward the exit side of frame 20 are disposed substantially inwardly of the surfaces 27, the width or height of side walls 24 being only slightly more than half the width or height of end walls 22 and 23, as will be clearly apparent from FIG. 5.

Over that portion of the height or width which is coextensive with the height or width of the side walls 24, end walls 22 and 23 are extended toward each other to have a thickness greater than those portions of end walls 22 and 23 which project beyond the surfaces 28 of side walls 24. This is best seen in FIG. 2, and the thickened portions of end walls 22 and 23, in conjunction with the side walls 24, define a substantially rectangular tongue receiving opening or passage whose height is slightly greater than the thickness of tongue 15 and which is slightly wider than the tongue. Opening 25 opens through the tongue entry face 21 of frame or head 20 and, at its opposite end, opens into a channel 25' defined by the portions of end walls 22 and 23 which extend beyond the faces 28 of side walls 24, the base of channel 25 being partially defined by the surfaces 28 of side walls 24. The projecting portions of end walls 22 and 23 taper in thickness somewhat toward the tongue exit faces 27, 27, so that channel 25 increases somewhat in width toward the exit face or surface of frame 20.

In accordance with the invention, the outer face 28 of each side wall 24 of frame 20 is formed with a recess extending longitudinally thereof, these recesses being generally triangular in cross section, as best seen in FIG. 5. Each recess 30 includes an outer wall. 31 which is substantially parallel to the inner surface of the associated side wall but preferably slopes away therefrom at a relatively small angle such as, solely by way of example, 5. Each recess further includes a sloped inner wall 32 which extends at an angle of the order of 45 with respect to the inner surface of the associated side wall.

Each recess 30 has located therein a substantially flat and thin metallic pawl 35 which is forced into or embedded in the associated side wall 24 at an angle such that it diverges slightly from the side wall 32 of the associated recess. Solely by way of example, if side walls 32 extend at an angle of with respect to the inner surface of the associated side wall, the substantially flat pawl 35 associated with the side wall may extend at an angle of substantially 40 relative to the inner surface of the associated side wall 24.

Each pawl 35 thus has a free inner end, and these free inner ends converge toward each other in a direction toward the exit faces 27. However, the free ends terminate'a short distance inwardly of the end surfaces of openings 25, the spacing of the free inner ends of pawls 35 being slightly less than the width, between side edges 17, 17, of tongue 15. Also, and by virtue of the aforementioned relative angular relationship, each pawl 35 has a slight clearance with the side wall 32 of the associated recess, allowing flexing of the pawl 35 toward the side wall 32 of the associated recess.

The manner in which the tie is used will be clear from FIG. 4, in which cable tie 10 is used to join several insulated conductors 11 into a cable bundle. For this purpose, tie 10 is wrapped around conductors 11 and the tapered portion 16 of tongue 15 is inserted through passage 25 and into channel 25, the insertion proceeding from the tongue entry face 21 toward the tongue exit faces 27. Tongue 15 is then drawn through head or frame 20 until it is tightly wrapped about conductors 11.

As tongue 15 is drawn through passage or opening 25, the pawls 35 are deflected outwardly and slide over the edges 17, 17 of tongue 15. As soon as the pulling effect on tongue 15 is released, the tongue will tend to retract, and this causes the chisel edges of pawls 35 to bite into the side edges 17, 17 of tongue 15 and thus anchor the tongue. After the tongue is thus drawn tight and anchored, the excess length of tongue may be cut or nipped off outwardly of the points of engagement between pawls 35 and the side edges 17 of the cable tie. This results in the cut edge of the cable tie lying substantially inwardly of the tongue exit faces 27, so that there is no out tongue edge projecting outwardly of the faces 27. Any attempt to pull tongue 15 further backwardly will result in the pawls 35 biting even more deeply into the edges 17, 17 of tongue 15.

Moreover, upon any attempt to pull tongue 15 backwardly, pawls 35, after only a very slight backward movement, will bear against the surfaces 32 of the recesses 30, and thus will be firmly supported over substantially their entire lengths, there being only a very short length of each pawl 35 projecting into the passage 25. This effectively prevents any backward bending of the ends of pawls 35, as can occur, for example, in the construction shown in the mentioned Schwester et al. US. patent. Furthermore, the retractive stress on tongue 15 of the cable tie is divided equally between the two pawls 35, so that each pawl is stressed to about only one-half the stress value to which a single relatively narrow pawl would be stressed. Consequently, the two pawls of the present invention, engaged with the side edges 17 of tongue 15, effectively prevent retraction of the tongue once the cable tie 10 has been tightened around a bundle of conductors 11, as shown particularly in FIG. 4.

FIG. 6 illustrates an alternative embodiment of the invention wherein the head 20' of the cable tie is formed to receive a marker or indicia for the cable tie. Referring to FIG. 6, the outer surface of the head 20' is formed with spaced parallel ribs 33 defining a dove-tail groove 34 which may be open at both ends, be closed at one end, or be closed at both ends. Groove 34 receives a conformingly shaped marker or indicia 40, which may carry suitable identifying data for the cable tie. The construction shown in FIG. 6 may result in some thickening of the outer wall 23' of the head 20, to provide the grooves 33, or the wall 23 may have the same overall thickness as the wall 23, and have the groove 34 cut into its outer surface.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. A cable tie, for binding plural insulated conductors or the like into a cable comprising, in combination, a

relatively elongated substantially flat flexible tongue having a pair of relatively wide opposite surfaces interconnected by relatively narrow and uninterrupted side edges; a substantially rectangular open frame integral with one end of said tongue, and including substantially parallel inner and outer endwalls interconnected by substantially parallel side walls to define a substantially rectanguar opening to receive the opposite end of said tongue; said frame having a tongue entry and tongue exit face; and at least one metallic pawl having a fixed end mounted in a respective frame side wall and having a free end extending inwardly toward the other side wall and converging toward said exit face, the free end of each pawl being spaced a substantial distance inwardly of said exit face; each pawl flexing as said tongue is drawn through said frame from said entry face, and biting into the material of a relatively narrow side edge of said tongue to prevent retraction of said tongue through said frame.

2. A cable tie, as claimed in claim 1, in which said end Walls have surfaces coplanar with said tongue exit face; said side walls having surfaces, facing toward said tongue exit face, which are spaced a substantial distance inwardly from said tongue exit face; whereby the portions of said end walls projecting beyond said side Walls define, with the exit end faces of said side walls, a channel communicating with said rectangular opening.

3. A cable tie, as claimed in claim 2, in which the exit face of each side wall is formed with a recess extending longitudinally thereof and opening toward said exit face of said frame; each pawl having an intermediate portion, which is intermediate its fixed end and its free end, lying in a respective recess.

4. A cable tie, as claimed in claim 3, in which said recesses are substantially triangular in cross section.

5. A cable tie, as claimed in claim 4, in which said pawls are substantially planar; each recess including an inner surface extending at an oblique angle with respect to the inner surface of the associated side wall, and each recess including an outer surface extending substantially parallel to the inner and outer surfaces of the associated side wall; each pawl lying closely adjacent the said inner surface of its respective recess.

6. A cable tie, as claimed in claim 5, in which said substantially rectangular opening has a width of the order of, but slightly greater than, the width of said tongue, and has a height of the order of, but slightly greater than, the thickness of said tongue, whereby to provide aslight clearance between the side edges of said tongue and the side edges of said substantially rectangular opening; each of said pawls extending into said rectangular opening a distance only slightly greater than the clearance of the associated side edge of the tongue with the adjacent side wall of said rectangular opening.

7. A cable tie, as claimed in claim 1, in which said substantially rectangular opening has a. width of the order of, but slightly greater than, the width of said tongue, and has a height of the order of, but slightly greater than, the thickness of said tongue.

8. A cable tie, as claimed in claim 1, in which said pawls are substantially planar and the width of each pawl is in excess of the thickness of said tongue.

9. A cable tie, as claimed in claim 1, in which the outer end wall of said substantially rectangular open frame has its outer surface recessed to receive a conforming indicia carrying cable tie identification data.

10. A cable tie, for binding plural insulated conductors or the like into a cable, comprising, in combination, a relatively elongated substantially flat flexible tongue; a substantially rectangular open frame integral with one end of said tongue, and including substantially parallel inner and outer end walls interconnected by substantially parallel side walls to define a substantially rectangular opening to receive the opposite end of said tongue; said frame having a tongue entry and tongue exit face; and a pair of metallic pawls each having a fixed end mounted in a respective end frame side wall and having free ends extending inwardly toward each other and converging toward said exit face, the free ends of said pawls being spaced a substantial distance inwardly of said exit face; said pawls flexing as said tongue is drawn through said frame from said entry face, and biting into the side edges of said tongue to prevent retraction of the latter through said frame; said end walls having surfaces coplanar with said tongue exit face; said side walls having surfaces, facing toward said tongue exit face which are spaced a substantial distance inwardly from said tongue exit face; whereby the portions of said end walls projecting beyond said side walls define, with the exit end faces of said side walls, a channel communicating with said rectangular opening; the exit face of each side wall being formed with a recess extending longitudinally thereof and opening toward said exit face of said frame; each pawl having an intermediate portion, which is intermediate its fixed end and its free end, lying in a respective recess; said recesses being substantially triangular in cross section; said pawls being substantially planar; each recess including an inner surface extending at an oblique angle with respect to the inner surface of the associated side wall, and each recess including an outer surface extending substantially parallel to the inner and outer surfaces of the associated side wall; each pawl lying closely adjacent the said inner surface of its respective recess; the plane of each pawl extending at an angle to the inner surface of the associated side wall, and which angle is less than the corresponding angle between the inner surface of the associated recess and the inner surface of the associated side wall; whereby to provide a slight clearance between the intermediate portion of each pawl and the inner surface of the associated recess.

References Cited UNITED STATES PATENTS 1,174,306 3/1916 Braaten 292-322 1,427,891 9/1922 Ziegler 40-21 3,106,028 10/1963 Baumgartner 40-21 3,118,200 1/1964 Bell 24-16 3,147,523 9/ 1964 Logan 24-16 3,186,047 6/ 1965 Schwester et a1 24-16 FOREIGN PATENTS 943,240 12/ 1963 Great Britain.

DONALD A. GRIFFIN, Primary Examiner. 

